How difficult is it to publish a paper in a Q1 journal? I mean, I know it depends on the quality of the research, but is it substantially more difficult than publishing in a Q2, Q3 or Q4 journal?
There is no one size fits all approach when it comes to publishing in Q1 journals. However, some of the ways that you can enhance your chances of publishing are:
Carefully choose journal
Read and strictly follow the authors guidelines, some journals also allow for pre-submission inquiries. Such inquiries can help in getting development advice on the manuscript from the journal editor.
Clearly explicate the international relevance of the paper
Indicate how the paper adds to the existing knowledge on the very topic
Provide a thorough review of literature throughout the paper, including methodology section; builds on the work of previous methodologists.
Tailor your implications for the audience of the journal.
David - my advice is that it usually will be harder to publish in a Q.1 publication than lower ranked. However, quality research (assessed by others - not just ourselves) is quality research wherever it is submitted. The rankings are there for a reason and it is assumed that a Q.1 journal is of 'high' quality. Of course, as with most things in life, this will not be the case 100% of the time. My advice to new authors is to decide 'do you aim high - or aim lower?' The advantage of aiming high is that there is a higher chance that, even if rejected, there is a higher chance of good quality reviewer feedback - which can then be used to further craft your manuscript for submission to the 'next journal on the rank' - and increase the chances of successful publication in that one. However, the caveat to that is that many Q.1 journals now undergo editorial screening before they go to reviewers - so one may not get that reviewer feedback. That said, that process is usually quick - within 1-2 weeks.
Aiming at lower ranked journals does have its merits as well. For those who lack confidence and higher chance of rejection may result in non-submission elsewhere, it is best to aim lower. Once an author has a publication 'under their belt' it often gives them the confidence to aim higher the next time. Many 'niche', specialised journals will also be lower ranked - but may be better to aim for for the research audience itself.
The attached chapter on barriers to avoid and tips to enhance success on disseminating research findings may assist.